My bike rim is 27.5x1.90 is it possible to fit a 27.5x2.2 tire on it?
I assume you mean that your current tire is 27.5x1.90. Rim widths are defined by internal width and external width. Regarding the tire the internal width is important.
As rims and tires for mountain bikes are becoming wider and wider, rim manufacturer often specify the recommended tire width for a rim and tire manufacturer specify the recommended rim widths.
1.90 and 2.20 are very common tire sizes for regular mountain bikes. So they should fit the rim. But as Daniel already commented: you have to check if there is currently enough room between the tire and the frame or fork. Note that wheels and tires bend under load and may rub at the frame even if there is a small gap between tire and frame. Usually bicycle and fork manufacturer define a maximum tire width for their frames and/or forks. As the tire manufacturer are not that consistent with their tire size labeling it may not be the whole truth. It also depends on the size of the side knobs.
So maybe you find a max tire width specification for your frame or you just have to guess if there will be enough room for the new tire.